Core drill head



Feb. 11, 193%. J H HOWARD ET AL ZQEQZQQ CORE DRILL HEAD Griginal Filed Ma 25, 1934 5 e m E W f A; F/efa 6: CA 74 AND JOHN hf Hon map 14 rive/v5) Patented Feb. 11, 1936 UNITED STATES CORE DRILL HEAD John H. Howard, Huntington Park, and Alfred (l.

Catland, Alhambra, Calif.; said Catland assignor to Globe Oil Tools Company, Los Nieto Calif., a corporation of California Original application May 25, 1934, Serial No.

7,2 7,499. Divided and this application December 15, 1934, Serial No. 757,692

8 Claims.

This invention relates to well drilling tools and relates more particularly to a core drill head. A general object of the invention is to provide a simple, practical core drill head that is particularly effective in its drilling action.

Another object of the invention is to provide a rock-core drill head or cutter head embodying a plurality of roller cutters that are positioned and related to be very rapid and eflicient in their cutting action.

Another object of the invention is to provide a cutter head or drill head for a rotary well drill embodying a plurality of roller cutters whose teeth or cutting partsare formed and related so that they do not track in their engagement with the earth formation.

Another object of the invention is to provide a core drill head of the character mentioned that is smooth running and that is operable to drill a full gauged bore and form or cut a large core.

The various objects and features of our invention will be fully .understood from the following detailed description of a typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is a side elevation of a core drill embodying the head of the present invention illustrating the head and one quarter of the drill in longitudinal cross section. Fig. 2 is an enlarged bottom view of the drill head. Fig. 3 is a fragmentary vertical detailed sectional view taken substantially as indicated by line 3-3 on Fig. 2 and Fig. 4 is an enlarged longitudinal detailed sectional view of one of the cutters and its bushmg.

This application is a division of our co-pending application Serial No. 727,499, filed May 25, 1934, entitled Well tool construction.

The present invention is concerned primarily with the arrangement, relative positioning and thecutting part structure of a plurality of roller cutters as employed in a drill for use in the rotary method of well drilling. The invention is capable of embodiment in well drilling tools varying considerably in character. Throughout the following detailed disclosure we will describe a typical application of the invention as employed in a core drill of the character described in our co-pending application referred to above, it being understood that the invention is not to be construed as limited or restricted to the specific application or embodiment about to be described.

The core drill illustrated in the drawing includes an outer barrel l comprising a main section l4 having a sub 15 on its upper end. The sub [5 is provided with a pin it for facilitating connection of the barrel with the drilling string. A sub or connecting member I! is provided on the lower end of thebarrel section l4 and carries a bit head sub 98. The drill includes a bit head l3 which is secured to the sub Hi. In the particular case illustrated. in the drawing a pin l9 on the lower end of the sub [8 is threaded into a socket 25 in the head E3 to secure the head to the sub. The 5 shoe or head l3 has acentral longitudinal opening 27 to receive the core. An inner barrel I I is arranged longitudinally within the barrel I n. The lower end of the inner barrel I l is threaded into the opening 20 of the sub [8. An annular space S 10 is provided between the barrels Ill and H to-carry circulation fluid to communicating ports 70- and E2 in the sub l8 and head l3. A core catcher I2 is arranged in the drill to retain the-core therein when the drill is withdrawn from the well. The

core catcher IZ comprises an annular body 2| shift-able in the opening of the sub I8. Flexible members 23 project longitudinally from the opposite ends of the body 2|. The projectingupper portions of the members 23 are bifurcated and 20 pointed to bite into the core. Slips 24 are provided on the projecting lower portions of the members 23. A portion of the wall of the opening 2b is inclined and the slips 24 are adapted to cooperate with the inclined wall[ The cooperation 25 between the slips 24 and the inclined wall'o'f the opening 20 forces the slips inwardly into'biting and gripping engagement with the core when the drill is raised.

The invention provides two groups or sets of cutters A and B for acting on the earth formation at the bottom of the well bore. 'In the particular application of the invention illustrated in the drawing the cutters A and B are carried by the head I3 to act on the bottom Wall of the well bore to drill an annular path or opening and leave a core which is received in the inner barrel ll. Sockets or recesses X and Y are provided'in the head 83 to hold or carry the cutters A'and B.

The recesses X and Y extend into the lower end 40 of the head l3 and are spaced between the inner and outer surfaces of the wall of the tubular head.

In accordance with the invention the recesses X and Y are circumferentially spaced being spaced to carry the cutters A and Bin the relationship contemplated by the invention. Two spaced pairs of recesses X are provided in the head l3 and two substantially diametrically opposite recesses Y are spaced between the pairs of recesses X. The inner and outer walls ofthe recesses X are inclined downwardly and outwardly and are substantially parallel. The opposing inner and outer walls of the recesses Y are inclined downwardly and inwardly with respect to cumferentially spaced lugs 28 are provided on the shoe or head |3 to provide ample material for the outer walls of the recesses X and Y. The lugs 23 are spaced apart to leave vertical or longitudinal external fluid passages 29 which conduct the circulation fluid upwardly around the cutter head. The recesses X and Y may have their sides open to the passages 29.

The cutters A and B are rotatable in their respective recesses X and Y and project downwardly beyond the lower end of the bit head |3 to act on the formation at the bottom of the well bore. The cutters A which we will term the outer cuters, engage the outer zone or portion of the bottom of the bore and project outwardly beyond the periphery of the bit head |3 to ream or cut the well bore to size. The cutters B which we will term the inner cutters, engage the inner zone or portion of the bottom of the well bore and trim the core for reception in the opening 21. The outer cutters A are frustoconical in their general configuration having flat opposite ends and a pitched or inclined periphery. In accordance with the invention peripheral cutting parts or teeth 36 are provided on the cutters A. The teeth 35 are preferably continuous and extend longitudinally between the opposite ends of the cutters.

It is a feature of the present invention that the cutting parts or teeth 30 of the two pairs of outer cutters A are formed and related so that they do not track in their engagement with the earth formation at the bottom of the bore. One cutter A of each pair of cutters A has straight axial cutting teeth 36 while the other cutter A of the pair has helical or spiralled cutting teeth 30. The spiralled cutting teeth 35 of the two cutters A at the opposite sides of the head B are pitched or spiralled in opposite directions, the teeth of one cutter being pitched in a right hand direction and the teeth of the other cutter being pitched in a left hand direction. The above described relationship between the cutting parts 35 of the several cutters A is important as it positively prevents the tracking of the teeth 35 of the cutters A as they act on or engage the earth formation in the well. The outer peripheral corners of the outer cutters A are bevelled or inclined to provide reaming cutting edges 3!. The cutting edges 3| may be substantially straight and are adapted to engage the earth formation at the side wall of the bore. The cutters A are provided with central longitudinal openings 32. Each opening 32 has an annular internal restriction 33 whose ends are inclined and constitute thrust shoulders 34 and 35. The outer portions of the openings 32 may be somewhat larger in diameter than the portions of the openings at the inner sides of the restrictions 33.

The inner cutters B are substantially cylindrical in their general configuration and have flat normal ends. Peripheral cutting teeth 36 are provided on the cutters B. The cutting parts or teeth 36 preferably extend from one end to the other of the cutters and may be continuous as illustrated in the drawing. The cutting teeth 35 are pitched or spiralled. It is a feature of the invention that the teeth 35 of one inner cutter B are pitched in a right hand direction while the teeth 36 of the other cutter B are pitched in a left hand direction. The cutting teeth 36 of the two cutters B being related in this manner cannot follow one another or track in their action on the formation in the well bore. The inner ends or corners of the cutting teeth 36 project inwardly to act on the core and are cut away or bevelled as at 31 to properly trim the core for reception in the opening 21. Central longitudinal openings 38 are provided in the cutters B. The openings 33 have annular restrictions between their opposite ends providing inwardly and outwardly facing shoulders 39 and 40.

The cutters A and B are mounted or supported to rotate about axes inclined with respect to the longitudinal axis of the drill. In accordance with the invention the outer cutters A are rotatable about axes inclined downwardly and inwardly relative to the central longitudinal axis of the tool and the outer cutters B are rotatable about axes inclined downwardly and outwardly with respect to the said axis. The means for rotatably supporting the cutters A and B illustrated in the drawing is fully described and claimed in our co-pending application referred to above. The cutter mounting or supporting means illustrated in the drawing includes bushings in the openings 32 of the cutters A. Each of these bushings includes an outer section 4| and an inner section 42. The inner end of the section 4| is adapted to cooperate with the shoulder 34 while the inner end of the section 42 is adapted to engage the thrust shoulder 35. Ex tensions 43 on'the sections 4| extend through the restrictions 33 to contact or engage the inner ends of the sections 42. ranged in keyways in interiors of the sections 4| and 42 .and their ends are welded to the sections so that they form connectors joining the two sections. Bushings 55 similar to the sectional bushings just described are arranged in the openings 38 of the inner cutters B. The sectional bushings 55 have shoulders 56 for cooperating with the shoulders 39 and 46 on the walls of the openings 38.

Pins 41 extend through the bushings of the cutters A to rotatably carry the cutters and similar pins 60 extend through the bushings 55 to support the inner cutters B. The pins 41 are inclined downwardly and inwardly and are passed inwardly through openings or notches in the outer wall of the head |3 to thread into openings 48 in the inner wall of the head. The pins 60 are inclined downwardly and outwardly and have their outer ends threaded into openings 58 in the outer wall of the head l3. ways or grooves 52 in the pins 41 receive the keys 45 so that the keys hold the bushings of the cutters A against rotation. The pins 60 are provided with grooves 6| for receiving the keys 62 of the bushings 55 whereby the keys hold the bushings 55 against turning on the pins. The pins 41 and 60 are locked against unthreading and displacement by lock pins 63 which enter openings in the pins. The lock pins 63 may be welded to the head I3. The cutters A and B are rotatably carried on their respective bushings so that their ends have suitable clearance with the opposite end walls of the recesses X and Y. Bosses 51 project from the inner walls of the recesses Y and enter the inner end portions of the cutters B.

During operation of the tool the cutters A and B engage or act on the formation at the bottom of the well bore and rotate independently about their respective axes. The frusto-conical cutters A being supported for rotation about downwardly and inwardly inclined axes have their cutting parts 30 acting in a substantially horizontal plane. The substantially cylindrical cutters B are rotatable about downwardly and out- Ribs or keys 45 are ar- Keywardly inclined axes so that their cutting parts 36 operate in inclined planes as they engage the formation. The cutting parts or teeth 30 of the cutters A .act on the outer portion of the bottom wall of the bore and project beyond the periphery of the head l3 to ream or cut the well bore to size. Each pair of cutters A includes a cutter having spiralled teeth and a cutter having axial teeth 3!! and the spiralled teeth of the cutters A at the opposite sides of the head are pitched in opposite directions. With this relationship between the cutting parts or teeth 30 the cutters are very rapid and efiicient in their cutting action. The formation and relating of the cutting parts 30 are such that the cutting parts do not track or follow one another in their action on the formation. The inner cutters B project inwardly at the lower end of the opening 21 so that their inner edges 31 trim the core. The cutters B overlap the cutters A in their action on the formation and because of the difference in the inclination of the cutters A .and B the combination of the two sets or groups of cutters provides a particularly effective and endcient drilling tool. The cutting parts or teeth 35 of the two inner cutters B are pitched in opposite directions and, therefore, cannot track or follow one another in their engagement with the earth formation.

Having described only a typical preferred form and application of our invention, we do not wish to be limited or restricted to the specific form and aplication herein set forth, but wish to reserve to ourselves any modifications or variations that may appear to those skilled in the art or fall within the scope of the following claims:

Having described our invention, we claim:

1. In a well drill, a tubular bit head, two substantially diametrically opposite cutters mounted on the lower end of the head to rotate about downwardly and outwardly inclined axes, spiralled cutting parts on the cutters, the cutting parts of one cutter being spiralled in one direction and the cutting parts of the other cutter being spiralled in the other direction, pairs of cutters mounted on the lower end of the head between said two cutters to rotate about downwardly and inwardly inclined axes, one cutter of each pair having straight axial cutting teeth, the other cutters of the said pairs having spiralled cutting parts.

2. In a well drill, a tubular bit head, two substantially diametrically opposite, substantially cylindrical cutters mounted on the lower end of the head to rotate about downwardly and outwardly inclined axes, spiralled cutting parts on the cutters, the cutting parts of one cutter being spiralled in one direction and the cutting parts of the other cutter being spiralled in the other direction, pairs of frustro-conical cutters mounted on the lower end of the head between said two cutters to rotate about downwardly and inwardly inclined axes, one cutter of each pair having straight axial cutting teeth, the other cutters of the said pairs having spiralled cutting parts.

3. In a well drill, a cutter head, spaced groups of spaced cutters projecting from the lower end of the head and rotatable about inclined axes, each cutter having longitudinally extending cutting parts, each group having a cutter with substantially straight cutting parts, and a cutter with spiralled cutting parts, and rotatable cutters spaced between said groups and projecting from the lower end of the head, the last named cutters having cutting parts spiralled in opposite directions.

4. In a well drill, a cutter head, spaced groups of spaced cutters projecting from the lower end' of the head and rotatable about inclined axes, each cutter having longitudinally extending cutting parts, each group having a cutter with substantially straight cutting parts, and a cutter with spiralled cutting parts, and cutters spaced between said groups and rotatable about axes inclined in the opposite direction to the axes of the cutters of said groups.

5. In a well drill, a cutter head, spaced groups of spaced cutters projecting from the lower end of the head and rotatable about inclined axes, each cutter having longitudinally extending cutting parts, each group having a. cutter with substantially straight cutting parts, and a cutter with spiralled cutting parts, and cutters spaced between said groups and rotatable about axes inclined in the opposite direction to the axes of the cutters of said groups, the last named cutters having cutting parts spiralled in opposite directions.

6. A head for a well drill including a body having recesses in its lower end, pairs of substantially frustro-conical cutters mounted in spaced pairs of recesses to rotate about inclined axes and to project from the lower end of the body, and substantially cylindrical cutters mounted in recesses between said pairs of recesses to rotate about axes inclined in the opposite direction to the axis of rotation of the first mentioned cutters and projecting from the lower end of the body, the last named cutters having spiralled cutting parts pitched in opposite directions.

'7. A head for a well drill including, an annular body having recesses in its lower end, spaced groups of substantially frustro-conical cutters mounted in recesses to rotate about downwardly and inwardly inclined axes and to project beyond the lower end and periphery of the body, said outters having longitudinal cutting parts, each group including a cutter having spiralled cutting parts and a cutter having axial cutting parts and substantially cylindrical cutters mounted in recesses between said groups to rotate about downwardly and outwardly inclined axes and to project beyond the lower end and the internal surface of the body.

8. A head for a well drill including, an annular body having recesses in its lower end, spaced groups of substantially frustro-conical cutters mounted in recesses to rotate about downwardly and inwardly inclined axes and to project beyond the lower end and periphery of the body, said cutters having longitudinal cutting parts, each group including a cutter having spiralled cutting parts and a cutter having axial cutting parts and substantially cylindrical cutters mounted in recesses between said groups to rotate about downwardly and outwardly inclined axes and to project beyond the lower end and the internal surface of the body, the last named cutters having spiralled cutting parts pitched in opposite directions.

JOHN H. HOWARD. ALFRED C, CATLAND. 

